Android custom keyboard layout leaving a margin of white at the side

Question

I'm working on a custom keyboard for Android, and I've run in to an issue where the keyboard seems to leave a white line/space at right, instead of filling the parent view... (don't mind the icons, it's simply placeholder graphic for now)

Below you can see my layout...

<Keyboard xmlns:android="http://schemas.android.com/apk/res/android"
    android:keyWidth="14%p"
    android:horizontalGap="0px"
    android:verticalGap="0px"
    android:keyHeight="60dp"
    >
    <Row>
        <Key android:codes="49" android:keyIcon="@drawable/rsz_emoji" android:horizontalGap="1%p" android:keyEdgeFlags="left"/>
        <Key android:codes="50" android:keyIcon="@drawable/rsz_emoji"/>
        <Key android:codes="51" android:keyIcon="@drawable/rsz_emoji"/>
        <Key android:codes="52" android:keyIcon="@drawable/rsz_emoji"/>
        <Key android:codes="53" android:keyIcon="@drawable/rsz_emoji"/>
        <Key android:codes="54" android:keyIcon="@drawable/rsz_emoji"/>
        <Key android:codes="48" android:keyIcon="@drawable/rsz_emoji" android:keyEdgeFlags="right"/>
    </Row>
    <Row>
        <Key android:codes="113" android:keyIcon="@drawable/rsz_emoji" android:horizontalGap="8%p" android:keyEdgeFlags="left"/>
        <Key android:codes="114" android:keyIcon="@drawable/rsz_emoji"/>
        <Key android:codes="116" android:keyIcon="@drawable/rsz_emoji"/>
        <Key android:codes="121" android:keyIcon="@drawable/rsz_emoji"/>
        <Key android:codes="111" android:keyIcon="@drawable/rsz_emoji"/>
        <Key android:codes="112" android:keyIcon="@drawable/rsz_emoji" android:keyEdgeFlags="right"/>
    </Row>
    <Row>
        <Key android:codes="1" android:keyIcon="@drawable/rsz_emoji" android:keyWidth="28%p" android:horizontalGap="8%p" android:keyEdgeFlags="left"/>
        <Key android:codes="46" android:keyIcon="@drawable/rsz_emoji" android:keyWidth="28%p"/>
        <Key android:codes="58" android:keyIcon="@drawable/rsz_emoji" android:keyWidth="28%p" android:keyEdgeFlags="right"/>
    </Row>
    <Row android:rowEdgeFlags="bottom">
        <Key android:codes="44" android:keyIcon="@drawable/globe" android:horizontalGap="8%p" android:keyEdgeFlags="left"/>
        <Key android:codes="47" android:keyIcon="@drawable/rsz_emoji"/>
        <Key android:codes="32" android:keyIcon="@drawable/rsz_emoji" android:keyWidth="28%p"/>
        <Key android:codes="1" android:keyIcon="@drawable/rsz_emoji"/>
        <Key android:codes="-5" android:keyIcon="@drawable/backspace" android:keyEdgeFlags="right"/>
    </Row>
</Keyboard>

As far as I can see, it's a matter of 1%p... But I'm a bit unsure how to fill it without messing up my alignments... E.g. changing the gap in the first row to 2 would fix it, but mess up the alignment.

Added extra code for you as requested...

My class extending InputMethodService:

    private KeyboardView kv;
    private Keyboard keyboard;

    @Override
    public View onCreateInputView() {
        kv = (KeyboardView)getLayoutInflater().inflate(R.layout.keyboard, null);
        keyboard = new Keyboard(this, R.xml.custom_keyboard);
        kv.setPreviewEnabled(false);
        kv.setKeyboard(keyboard);
        kv.setOnKeyboardActionListener(this);
        return kv;
    }

    @Override
    public void onPress(int primaryCode) {

    }

    @Override
    public void onRelease(int primaryCode) {

    }

    @Override
    public void onKey(int primaryCode, int[] keyCodes) {
        InputConnection ic = getCurrentInputConnection();

        if (primaryCode == Keyboard.KEYCODE_DELETE) {
            ic.deleteSurroundingText(1, 0);
        } else {
            Drawable mDrawable = ResourcesCompat.getDrawable(getResources(), R.drawable.rsz_emoji, null);
            Bitmap mBitmap = ((BitmapDrawable)mDrawable).getBitmap();
            String path = MediaStore.Images.Media.insertImage(getContentResolver(), mBitmap, "Emoticon", null);
            Uri fileUri = Uri.parse(path);

            Intent picMessageIntent = new Intent(Intent.ACTION_SEND);
            picMessageIntent.setPackage("com.android.mms");
            picMessageIntent.putExtra(Intent.EXTRA_STREAM, fileUri);
            picMessageIntent.setType("image/png");
            picMessageIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(picMessageIntent);
        }
    }

    @Override
    public void onText(CharSequence text) {

    }

    @Override
    public void swipeLeft() {

    }

    @Override
    public void swipeRight() {

    }

    @Override
    public void swipeDown() {

    }

    @Override
    public void swipeUp() {

    }

My Keyboard.xml

<?xml version="1.0" encoding="utf-8"?>
<android.inputmethodservice.KeyboardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/keyboard"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    />

Styles.xml

<resources>
    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>
</resources>

Manifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="CENSORED" >

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <!-- Declares the input method service -->
        <service android:name=".CENSORED"
            android:label="@string/keyboard_name"
            android:permission="android.permission.BIND_INPUT_METHOD">
            <intent-filter>
                <action android:name="android.view.InputMethod" />
            </intent-filter>
            <meta-data android:name="android.view.im"
                android:resource="@xml/method" />
        </service>
    </application>

    <uses-permission android:name="android.permission.INTERNET" />
</manifest>